Expose a seekable range at 0 for streaming sources with duration.

media/blink/webmediaplayer_impl.cc

Index: media/blink/webmediaplayer_impl.cc
diff --git a/media/blink/webmediaplayer_impl.cc b/media/blink/webmediaplayer_impl.cc
index 6b5cadb08c5fec7dddd6bc8dc6ff6679c7108b60..16c5042363523d67dd216548db85a8a023453534 100644
--- a/media/blink/webmediaplayer_impl.cc
+++ b/media/blink/webmediaplayer_impl.cc
@@ -15,6 +15,7 @@
 #include "base/debug/alias.h"
 #include "base/debug/crash_logging.h"
 #include "base/debug/trace_event.h"
+#include "base/float_util.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
 #include "base/single_thread_task_runner.h"
@@ -487,21 +488,15 @@ blink::WebTimeRanges WebMediaPlayerImpl::buffered() const {
 blink::WebTimeRanges WebMediaPlayerImpl::seekable() const {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
-  // If we haven't even gotten to ReadyStateHaveMetadata yet then there
-  // are no seekable ranges.
-  if (ready_state_ < WebMediaPlayer::ReadyStateHaveMetadata)
-    return blink::WebTimeRanges();
-
-  // We don't support seeking in streaming media.
-  if (data_source_ && data_source_->IsStreaming())
-    return blink::WebTimeRanges();
-
-  // If we have a duration then use [0, duration] as the seekable range.
+  // Media without duration are considered streaming and should not be seekable.
   const double seekable_end = duration();
-  if (!seekable_end)
+  if (!base::IsFinite(seekable_end))
     return blink::WebTimeRanges();
 
-  blink::WebTimeRange seekable_range(0.0, seekable_end);
+  // If we have a finite duration then use [0, duration] as the seekable range;
+  // unless it's a streaming source, in which case only allow a seek to zero.
+  blink::WebTimeRange seekable_range(
+      0.0, data_source_ && data_source_->IsStreaming() ? 0.0 : seekable_end);
   return blink::WebTimeRanges(&seekable_range, 1);
 }